The invention relates to a fan assembly, and in particular to a fan assembly applicable to a light source producing heat.
With the continuous development of electronic devices, heat dissipation systems become necessary as temperature is significantly increased due to heat produced during operation. If heat is not appropriately dissipated, high temperature causes performance to deteriorate and may cause the electronic devices to fail. Particularly, since semiconductor and integrated circuits (IC) design has improved, the integrated circuit size has been reduced and the number of transistors per unit area has substantially increased, further concentrating heat energy. Thus, a heat dissipation system is required to effectively dissipate the excess heat and maintain working temperature.
Fan assembly is the most popular heat dissipation apparatus. FIG. 1A is a top view of a conventional fan assembly, and FIG. 1B is a cross section of FIG. 1A. As shown in FIGS. 1A and 1B, the conventional fan 10 comprises a frame 11, an impeller 15, and a motor (not shown). The motor is disposed in a motor base 12 to drive the impeller 15. The frame 11 comprises a body with an opening defined therein. The motor base 12 disposed in the frame 11 is supported by a plurality of ribs 13. The ribs 13 can be cylindrical, arced, or streamlined. The impeller 15 comprises a plurality of radially arranged blades 14.
In FIG. 1B, as known, when two ribs 13 are both connected to the motor base 12 and the frame 11, they are not located along the same diameter of the impeller 15, and the cross section of the two ribs 13 would be discontinuous. For clear illustration, however, the ribs are shown in their entirety in FIG. 1B.
During rotation of the impeller 15, a gap is formed between the frame 11 and the blades 14 to prevent contact therebetween, which produces friction and noise, as shown in FIG. 1A. If the fan assembly 10, however, is applied to an optical machine to dissipate heat of the light source (lamp) L, the emitted light Lp may partially penetrate the gap between the frame 11 and the blades 14, causing light loss, as shown in FIG. 1B. Consequently, projected light intensity is reduced, and if escaped light Lp continuously illuminates other areas or objects such as a desk, the surface of the desk can be damaged by the light. The escaped light not only damages the surroundings but also causes safety concerns.